Canvas is heavy cloth.To canvass means to survey opinion or to solicit votes.

The words canvas and canvass sound identical, but their meanings are very different.

Canvas

The nouncanvas
(with one s at the end) refers to a heavy woven cloth of hemp, flax or cotton. It is used for sails, tents and paintings. The word canvas is also used
figuratively for the floor of a boxing or wrestling ring (i.e., they are often not made of canvas).